Adolescence is a time of heightened vulnerability for risk taking behavior and poor decision making that can give rise to substance use and externalizing behavior. Emerging evidence from developmental neuroscience suggests that risk taking behavior increases during adolescence partly due to changes in the brain's neural circuitry. Regions implicated in cognitive control (e.g., the prefrontal cortex), which is involved in self-regulation, develop more slowly relative to regions response to reward (e.g., the ventral striatum), which are involved in reward evaluation and sensitivity. This neural imbalance may hinder appropriate evaluation of risk and bias youth towards risky decisions. Despite these advances, there currently is little understanding of how these neurological developments interact with fundamental social processes during the adolescent period. Families from Mexican and other Latin American backgrounds place particular value on family connection and support, often referred to as familism or family assistance. Yet family assistance can be both rewarding and stressful for adolescents. We believe that family assistance is a basic aspect of family relationships that can shape the neurobiology of risk taking depending upon whether adolescents find it to be either a rewarding or stressful experience, and we address these possibilities with the following two objectives: (1) identify the links between the rewards of family assistance and the neural mechanisms associated with risk taking, and (2) identify the links between the stress of family assistance and the neural mechanisms associated with risk taking. A total of 45 adolescents from Mexican backgrounds who are participating in a larger study of daily family assistance will be recruited to participate in a neuroimaging study. In addition to reporting daily levels of family assistance, reward, and stress across a 14 day period as part of the parent R01, these 45 adolescents will provide salivary cortisol at 4 time points each day for 4 of these days. Adolescents will then be brought to an fMRI lab in which they will engage in risk taking tasks while being scanned by a 3 Tesla Siemens Trio MRI scanner using standard scanning procedures. After appropriate preprocessing of the fMRI data, the associations of family assistance, reward, stress, and cortisol with neural activity will be estimated by focusing on a priori regions of interest implicated with cognitive control and reward. PUBLIC HEALTH RELEVANCE: Taking underlies many behavioral and health problems that contribute to the public health burden during the adolescent period, such as substance use and externalizing behavior. Recent advances in developmental neuroscience have identified key neurobiological underpinnings of adolescent risk taking, but there is little understanding of how the neural mechanisms interact with other social and biological processes in order to create or prevent risk. The primary focus of this competitive revision is to examine how a fundamental aspect of family relationships - family assistance - can shape the neurobiology of risk taking depending upon whether adolescents find such family assistance to be rewarding or stressful.